Protective system



May 18, 1937. F. PEDATELLA PROTECTIVE SYSTEM Filed Oct. 10, 1935 Jgw INVENTOR Patented May 18, 1937 UNITED Q STATESv "PATENT/OFFICE PROTECTIVE SYSTEM Frank Pedatella, New 'Kensingto'n, Pa.

Application October 10, 1935, Serial No. 44,467

7 Claims.

My invention relates to a system for indicat- 1 ing the condition of an electric circuit'and for controlling the circuitunder certain conditions. .1

The system includes means for protecting the load devices in the circuit in the event that a circuit breaker which has been automatically opened by an overload current is closed while an overloading defect is still present in the circuit. 10 By my invention, I provide load-limiting means in the form of a circuit interrupter or overload M switch for opening acircuit, upon the occurrence of a fault therein, and maintaining the circuit open until intentionally reclosed. The provil5 'sion of such means obviates the necessity of using fuses in the circuit, and provides convenientmeans whereby the circuit can again be put in an operative condition in a convenient and positive manner. If the circuit is manually closed control box to cease to function.

I. also provide means by I theoperation of 25 which the current is entirely out off momentarily *from the control box and the electric circuits connectedthereto; The operation of such means described.

As shown in thedrawing, an electrical load r device' l is adapted to be connected toa. supply-- circuitZ through thecontacts-of a manually operable circuitbreaker or overload switch 3 and u-a control box 4.- Any number of electrical load circuits may be connected tothe said control- 40 box, for example, all the devices used on as'ingle floor of a building. Each of the said devices has a circuit breaker, similar to circuit'breaker 3, in

. series in the circuit, as illustrated by' the device 5 and an associated overload switch 6. The de household appliances, lamps, motor-driven appliances orheating device. The manually operable circuit breaker or overload switch 3,-consists of a 5 snap-action switch whichcan be manually operated between closed and-open positions and I which, when operated, retains its-position. In

1 addition; the switch maybe opened by the energl- F zation of a solenoid I acting on a core 8." Core 8 55 is attached to the: operating mechanism of the While the faulttherein is not cleared-the reclosing will operate a circuit ina control box and cause all the electric devices connected to the The inventionmay be readilyunderstood by vices l and 5, for example, may be of any'characsuch asindustrial devices or theordinary switch so that when the solenoid 1 is energized the circuit is opened. Once opened, the switch is closed by-a manual operation.

- Thecontrol box 4 has therein a main relay or circuit breaker -9-which-is operated by a relatively low-resistance overload or tripping-coil l0 acting on core H and by arelatively high-resistance closing coil Itacting on core l3. One end of tripping coil I0 is connected to one of a pair of contacts Ilia, and the other end to one of the supply circuit conductors leading from the control'box to the load devices. One end of closing coil -I-2 is connected to one of a pair of contacts lza andthe other end is connected through a lock-outrelay or circuit breaker M to the other of the supply circuit conductors leading from the control box to the loaddevices.

Connected to cores H and I 3 is a member 15 so adapted that whenopeningcoil IU is adequately energized, the

contacts lZa are bridged and when closing coil l2 .is energized contacts l0a are bridged. Contacts Illa whenbridged complete the supply circuit. The lock-out relay I4 is connected in parallel with ,trlpping coil l0 and contacts Illa, and when energized opens contacts Ma. A normally closedswitch I6 is connected in the supply circuit. The function of this switch willbe later 'Ihe-drawing illustrates the conditions of the circuit solong as thedevices which are in use are drawing only normal current from the supply circuit 2. .The'power currentpasses from one "side of supply line 2, through contact Ilia, coil [0, through the various devices, and thence to the other side of the-supply circuit.

normally subject only to the relatively small voltagedrop through the overload or tripping coil land is, therefore, not energized sufiiciently to open its contactsso long as normal current I is being consumed by the devices.

If an overload occurs-,.due to any defect in the device I, for example, or in the circuit in which it is connected, the excessive current flow resultingiwill cause the overload switch 3 to move core8 and open the defective circuit. The operation of the other devices, such as device 5,'will not be-afiected. If the overload -switch3 is then manually operated to close the circuit While the defect remains, an overload current passes -through tripping coil "Land actsupon core H to open: contacts [0a. This removes the shunt from across the coil of lock-out relay [4 which is then subject to the-full line voltage andoperates to open its contacts Ma. The coil of lock-out The coil 3 ofthe lock-outrelay or circuit breaker I4 is Cal relay it remains energized and its contacts Ma open as long as any of the load circuits are closed. The contacts |2a are bridged immediately after the operation of lock-out relay l4, it being understood that the relay l4 operates immediately after the circuit breaker member l5 moves to open the contacts Illa and while such member I5 is still in the course of its movement to bridge the contacts I211.

The current passing through the coil of lockout relay it, due to its resistance, is insufiicient to operate the devices connected to control box 4 and the fact that these devices cease to operate will warn that there is a defect in some device connected to the circuit or in the circuit itself.

After the defect has been remedied, the normal circuit condition will be restored to the system by momentarily opening the switch 16, which is manually operated. The opening of the circuit at switch !8 will deenergize the look-out relay coil M and will permit its contacts Ha to re-close. The closing coil i2 is thus connected directly across the supply circuit through the auxiliary contacts 52a. This attracts core l3 which opens auxiliary contacts l2a. Closing coil I2 is deenergized and then the contacts Illa are bridged. The circuit, through circuit breaker 9, is thus restored to normal operating condition. The load devices which are in normal operating condition will immediately begin to function, and the device in which the fault is present, either in the device itself or in its associated circuit, will not function. So, also, if the current to all the load devices is shut off, the cessation of current flow will cause the coil M. to be deenergized, and as soon as current is again connected to any load device the normal circuit conditions in control box 4 will be restored.

The overload switches 3 and 6 are more sensitive to overload current than the main relay or circuit breaker 9. Thus, upon the occurrence of a defect in the circuit of a load device I or 5, the switch (3 or 5) in such circuit will operate before overload current adequate to operate the circuit breaker is reached. However, it will be manifest that if the switches 3 and 6 and circuit breaker 9 are equally sensitive, an overload in one load circuit will operate the circuit breaker 9 simultaneously with the switch (3 or 6) in such circuit. If the overloaded circuit is the only load circuit in service at the moment overload occurs, the coil of relay i i will not be energized, and the contacts Ma will remain bridged, so that when the switch it (or the switch (3 or 6) of the sound or normal load circuit) is closed, the coil I! of the circuit breaker will be energized, and the contacts lfia will be bridged for normal operation of all but the overloaded circuit in which the protective switch (3 or 6) stands in open position. If the latter switch be inadvertently closed the system will operate in the manner already described. If both load circuits are in service, when one of them is overloaded, and, as above mentioned, the switch of the overloaded circuit and the circuit breaker both move into emergency position, the relay M will open and remain open, due to the current flowing through the sound or unaffected load circuit. In such case the circuit breaker 5 may be returned to normal position across the contacts Illa, either while the switch in the defective circuit stands open, or after the defect in such circuit has been remedied, by momentarily opening the switch l6, or by opening and reclosing the sound load circuit.

It will be thus seen that by the use of my device the use of fuses to protect the system can be entirely eliminated, and, even though a defect occurs in one circuit, none of the load devices connected to the supply line through the control box will be injured by an overload or by an attempted closure of a circuit breaker or switch when a defeet is still present in its associated circuit. The devices in which no fault is present will operate precisely as though all the circuits connected to the control box were in operating condition. My arrangement provides a safe, convenient, positive, and inexpensive arrangement for the protection of electrical devices from injuries due to overloads.

While I have shown and specifically described the present preferred embodiment of my invention, it will be understood that the invention may be otherwise constructed and embodied within the scope of the following claims.

I claim:

1. In apparatus for eliminating the customary use of fuses in an electric system including a plurality of load circuits connected to a supply source and each subject to the control of a manually operated switch, the combination of a circuit breaker for disconnecting all of said load circuits from said source, opening and closing coils for said circuit breaker, opening coils severally cooperating with said switches, whereby, when an overload condition occurs in any of said load circuits, the switch which normally is manually operated for the control of such circuit is automatically opened, the opening coil of said circuit breaker being responsive to current drawn from said source upon the manual reclosing oi the automatically opened switch while overload condition still exists, and means operated by said current for preventing energizing of the closing coil of said circuit breaker.

2. In apparatus for eliminating the customary use of fuses in an electric system including a plurality of load circuits connected to a supply source and each subject to the control of a manually operated switch, the combination of a circuit breaker for disconnecting all of said load circuits from said source, opening and closing coils for said circuit breaker, opening coils severally cooperating with said switches, whereby, when an overload condition occurs in any of said load circuits, the switch which normally is manually operated for the control of such circuit is automatically opened, the opening coil of said circuit breaker being responsive to current drawn from said source upon the manual reclosing of the automatically opened switch while overload condition still exists, means operated by said current for preventing energizing of the closing coil of said circuit breaker, and manually operable means for rendering said last-mentioned means ineffective.

3. In apparatus for eliminating the customary use of fuses in an electric system including a plurality of load circuits connected to a supply source and each subject to the control of a manually operated switch, the combination of a circuit breaker for disconnecting all of said load circuits from said source, opening and closing coils for said circuit breaker, opening coils severally cooperating with said switches, whereby, when an overload condition occurs in any of said load circuits, the switch which normally is manually operated for the control of such circuit is automatically opened, the opening coil of said circuit breaker being connected in series with the load and adapted to open the circuit breaker upon the manual reclosing of the automatically opened switch while overload condition still exists, and a lock-out relay in parallel with said opening coil and adapted to be operatively energized substantially simultaneously therewith for preventing energizing of the closing coil of the circuit breaker.

4. In apparatus for eliminating the customary use of fuses in an electric system including a plurality of load circuits connected to a supply source and each subject to the control of a manually operated switch, the combination of a circuit breaker for disconnecting all of said load circuits from said source, opening coils severally cooperating with said switches, whereby, when an overload condition occurs in any of said load circuits, the switch which normally is manually operated for the control of such circuit is automatically opened, said circuit breaker having an opening coil which is normally connected in series with the load and adapted to open the load circuit upon reclosing of the automatically opened switch while overload condition still exists, and means for reclosing the circuit breaker.

5. In apparatus for eliminating the customary use of fuses in an electric system including a plurality of load circuits connected to a supply source and each subject to the control of a manually operated switch, the combination of a circuit breaker for disconnecting all of said load circuits from said source, opening coils severally cooperating with said switches, whereby, when an overload condition occurs in any of said load circuits, the switch which normally is manually operated for the control of such circuit is automatically opened, said circuit breaker having an opening coil which is normally connected in series with the load and adapted to open the load circuit upon reclosing of the automatically opened switch while overload condition still exists, and a closing coil for closing said circuit breaker when the current supply is interrupted.

6. In apparatus for eliminating the customary use of fuses in an electric system including a plurality of load circuits connected to a supply source and each subject to the control of a manually operated switch, the combination of a circuit breaker for disconnecting all of said load circuits from said source, opening coils severally cooperating with said switches, whereby, when an overload condition occurs in any of said load circuits, the switch which normally is manually operated for the control of such circuit is automatically opened, said circuit breaker having an opening coil which is normally connected in series with the load and adapted to open the load circuit upon reclosing of the automatically opened switch while overload condition still exists, and a closing coil for closing said circuit breaker when the current supply is interrupted.

'7. In apparatus for eliminating the customary use of fuses in an electric system including a plurality of load circuits connected to a supply source and severally subject to the control of manually operated switches, the combination of opening coils severally cooperating with said switches, whereby, when an overload condition occurs in any of said load circuits, the switch which normally is manually operated for the control of said circuit is automatically opened, a circuit breaker controlling connections between said load circuits and said source, said circuit breaker in cluding an opening coil connected to open the circuit breaker upon the reclosing of the automatically opened load circuit while overload condition still exists, electric lock-out means adapted to be energized substantially simultaneously with the opening coil of said circuit breaker for preventing reclosing of the circuit breaker while overload remains in connection with said source.

FRANK PEDATELLA. 

